Hi,
NU stands for Network Upgrade, there are two a year or so.
The next one is Blossom which should activate on October 28th.
The first link in this post by zooko shows what the current pipeline looks like.
I would read that post, but here is the direct link
The deadline to get a ZIP (Zcash Improvement Protocol) to be put in NU4 is August 31st.
Here is a great post from nathan about community written ZIPs. (Nathan-at-least is in charge of the ZIP and NU processes.)
Note that the most active person on the forum who has responsibility for zips on a ownership level is daira, but I have found all members of the ECC very willing to help.
and this is more about ZIPs and NU3 (the upgrade about to happen)
Here is a post from str4d that gives more links about the ZIP’s that the ECC make.
Hopefully this will give you a better idea.
Let me know if I can help any further.